Hypermobility vs Flexibility: Do You Know the Difference?

When most people think of flexibility, they picture someone like a dancer, a gymnast, or a yogi – someone who can easily move their body into deep-looking shapes like full forward splits (hanumanasana) or yoga’s king pigeon pose (eka pada rajakapotasana). But most people are operating under an incomplete definition of what it means to be flexible. Flexibility doesn’t simply mean the ability to take your joints through great ranges of motion, regardless of what tissues stretched to get you there. We’re lucky enough to have a growing movement in the yoga world today that seeks to update our traditional understanding of yoga with the grounded scientific knowledge of biomechancs. As a cornerstone of that movement, we need to make sure we understand what true flexibility means and how it’s different from a term that many people mistakenly conflate with flexibility: hypermobility.

HYPERMOBILITY VS. FLEXIBILITY

Here’s the deal: the term flexibility refers to muscles (and their associated fascia) while the term hypermobility refers to ligaments. Muscles and ligaments are two distinct types of tissues which perform very different functions in the body. Here’s a quick anatomy primer (it’s a bit oversimplified, but still helpful!):

A muscle is a contractile tissue which crosses over one or more joints in your body. When a muscle contracts, it exerts a pulling force on the bones to which it attaches. Ligaments, on the other hand, are short bands of fibrous connective tissue which connect bone-to-bone and effectively “fasten” our joints together. Unlike muscles, ligaments don’t contract, generate force, or create movement in the body. Instead, as my biomechanics teacher Katy Bowman says, the ligaments serve as the “seat belts” of our joints. They can be considered our built-in back-up system to stabilize our joints if our body moves in a way that would otherwise take a joint beyond its normal range of motion.

SHOULD WE STRETCH OUR MUSCLES OR LIGAMENTS?

When we stretch, our intention should be to elongate our muscles and not our ligaments. When muscles stretch, they return to their original length after the stretch is released – a tissue property called elasticity. But when ligaments stretch, they behave elastically during just the first tiny bit of the stretch, and if they’re stretched beyond that point, they will permanently stay at that new length and are referred to as lax. Lax ligaments can no longer stabilize our joints for us and are a source of chronic pain and injury for many people. Overstretching our ligaments is therefore decidedly uncool.

Although many people have been told that they’re “hypermobile”, only a small percentage of the population actually has a condition of generalized, all-over joint hypermobility. In reality, most people who think of themselves as “hypermobile” simply have a specific number of joints whose ligaments have become lax. That ligament laxity is usually the result of the joint being habitually loaded beyond its normal range of motion, which is what happens when we “flop into our joints” time-and-time again without muscular support. Once you have the ability to hyperextend a joint, you will always have that ability, because you can’t “stiffen” your ligaments back up once they’ve become lax.

Here’s a visual example of what hypermobility looks like when it happens at the elbow joint, a common site of too much mobility in yogis (including me!)

Here are my nice elbows at their healthy normal end range of motion in extension: 180 degrees.

And here are my same elbows at beyond 180 degrees. These elbows are no longer within the normal range of motion for extension. They’re in hyperextension, which is an unhealthy, unstable place for them to be. For the health of our joints and therefore our whole body, we need to work to keep our joints out of hyperextension as much as possible.

HYPERMOBILITY = LACK OF FLEXIBILITY (SAY WHAT?)

As surprising as it sounds, hypermobility goes hand-in-hand with tight muscles. In fact, many people develop hypermobility in their joints in the first place as a result of tightness in muscles close to that joint. Additionally, one classic rule that our bodies tend to follow is that they prefer to move via “the path of least resistance”. It’s always easier to move your body where you’re already mobile and have less resistance than a place that is stiff and unyielding. Therefore, if a person with lax ligaments attempts to stretch her/his actual muscles, their clever body will sneakily rearrange itself into familiar and easy hypermobility land (the aforementioned path of least resistance), thereby bypassing the intended muscular stretch and loading the ligaments instead. Unless we learn how to override this tendency of the body with intelligent alignment, our stretches will result in joints whose hypermobility is reinforced and muscles that weren’t stretched at all, every time we stretch. And who wants that?

HYPERMOBILITY MASKING AS FLEXIBILITY

This last point is possibly the most important one of this entire article (and maybe of this whole blog!) Many poses in the practice of yoga require great ranges of motion from our bodies. In fact, there are quite a few asanas which can’t be performed to their fullest expression without our joints exceeding their normal range of motion. Put another way, many yoga poses require hypermobility in order to achieve.

Let’s examine full king pigeon pose (eka pada rajakapotasana), a pose we mentioned earlier in this post. This is an undeniably aesthetically-pleasing, graceful asana, and when we see someone doing it, we often think, “Wow, look at how flexible that person is!”

But remember what we’ve learned about the difference between flexibility (muscles) and hypermobility (ligaments)? Despite the fact that this pose is so pretty that it has graced the cover of Yoga Journal on many occasions, the biomechanical truth of this asana is that it cannot be achieved unless the low back (lumbar spine) moves into a high degree of hyperextension, which you can probably see if you look closely at this yogi’s lower back area. The normal range of motion for extension of the lumbar spine is somewhere between 20-35 degrees, but this yogi’s lumbar spine has extended far beyond that amount, creating compression and degenerative forces in this vulnerable area of the body. In addition, the fact that the lumbar spine is in such an extreme arc in this pose means that the yogi is able to bypass stretching her tight hips and shoulders. A general rule of thumb for working with the body is that we want to stabilize where we’re too mobile and mobilize where we’re too stable. But in this pose, we’re doing the exact opposite, allowing our tight spots to remain tight and our overly mobile spots to become more mobile and therefore more unstable.

It’s not enough to approach our yoga poses as “stretches.” We need to consider where the stretch is taking place and what tissues are stretching to make the shape happen. A yogi performing full king pigeon pose might look flexible, but the truth is that although she has moved her body through a great range of motion, it’s hypermobility, not flexibility, that allowed this motion.

I’m excited to be part of the growing movement within the yoga community that seeks to merge our grounded scientific knowledge of the body with our understanding of yoga. And as a cornerstone of this movement, we need to make a very clear distinction between what is flexibility and what is hypermobility, and use that understanding to make informed decisions about which asanas we choose to practice and why. My goal in my yoga practice and teaching is cultivating the long-term health and well-being of our bodies, our body-mind connection, and our lives as a whole, and this goal is contingent on emphasizing true flexibility and downplaying hypermobility as much as possible in our practice.

~

Jenni Rawlings loves to weave her natural interest in anatomy and biomechanics into her yoga teaching. She is grateful to so many teachers who inspire her, most notably amazing biomechanist Katy Bowman. You can find out more about Jenni at www.jennirawlings.com.

We stiff yogis, if we practice assiduously, feel it more (and get more mental and physical benefits) than those gumbies who have to stretch into tomorrow in order to feel ANYTHING. And with regards to strength postures, a similar rule applies …

It pays the more flexible to not get injured for when that day that they need their hips to stay in ONE place, comes … because maybe yoga could stand to be less of a competitive sphere … but we all know that will not happen 🙂 …

I am really flexible (maybe hypermobile?) and I have been since I was a little kid. I can’t actually feel a lot of what a stiff person can feel. I long for a little stiffness so I can really feel what I am doing in certain asanas. I always tell people who gasp when I cross my ankles behind my head that I would give anything for shoulders that didn’t pull out of socket or having to constantly focus on rolling in my thighs because of my insane hips. Stiffness can be blessing.

Thank you for an interesting article! It would be helpful to compare this photograph with one in which someone is doing full King Pigeon pose “correctly” i.e. with flexibility rather than hypermobility.

Interesting article. Are you saying that in doing asana such as Rajakapotasana one cannot avoid hyperextension and therefore these poses should not be performed ?

Quote: …. the biomechanical truth of this asana is that it cannot be achieved unless the low back (lumbar spine) moves into a high degree of hyperextension, which you can probably see if you look closely at this yogi’s lower back area ….

I was wondering the same thing. I’ve been taught to strengthen and support those areas where hyperextension is common (for me) not to avoid them all together. This article makes it seem as though those poses will degenerate ligaments beyond repair without any alternative. Hmm.

Agree with Dwayne and other posters. Would add that this article misses several points and is incorrect in others. Examples:

“only a small percentage of the population actually has a condition of generalized, all-over joint hypermobility”

Actually, joint hypermobility syndrome is thought to affect up to 15% of the population. This is the published number. That’s not small. It is also a spectrum.

“Instead, as my biomechanics teacher Katy Bowman says, the ligaments serve as the “seat belts” of our joints. They can be considered our built-in back-up system to stabilize our joints if our body moves in a way that would otherwise take a joint beyond its normal range of motion.”

The ligaments and muscle work in concert. If anything, the muscles are the dynamic stabilizers of the joints, backing up the ligaments. The approach the author uses is fundamentally backward; taking this approach misses the point of strengthening the muscular stabilizers to back up loose ligaments and capsule. Which leads to the next point…

This is surprising because it is incorrect. Typically, people with joint hypermobility do not have tight muscles (I work with them as patients all the time). Making statements like this leads to misunderstandings of how to work with this condition, which is through strengthening the muscular stabilizers. I would challenge the author (or her biomechanics guru) to provide one reference supporting that people with joint hypermobility have tight muscles. This is an area that has been extensively studied.

Thanks so much for your responses to my article, Everybody! I’m so glad that the piece has been well-received by most of you! I hear the requests for offering practical advice on how to keep out of hyperextension in your own practice, but I think that’s a bigger-picture issue that is better suited for a full training or some one-on-one-work with people – it’s not a succinct, easy prescription that can be summarized into a small blog post. This article was more meant to raise awareness that hypermobility is a requirement for many of yoga’s asanas, and if one of our goals in our yoga practice is to cultivate longevity and sustainability in our body, then these types of poses do not serve that goal.

As for @scrutinizing’s comments, the description in my article of the ligaments as the “seat belts” of a joint is valid. Of course the muscles work as dynamic stabilizers of the joints – calling the ligaments the “seat belts” of the joints does not negate this. One can think of the ligaments as the seat belts and the muscles as the brakes – if muscles don’t work to stabilize a joint like they should (like the brakes of a car would), then the ligaments are there to back them up (like seat belts in a car if the brakes aren’t applied properly).

As far as the hypermobile patients you work with and the tightness of their muscles, I wonder if you’re using a objective system of alignment markers to guide you in assessing the flexibility of their muscles. And I also wonder what definition you’re working with when you refer to “tight” muscles: short, hypertonic, unyielding, etc.? I work with many yoga students with joint hypermobility and every one of them demonstrates significant corresponding muscle tightness.

Of course we want to try to balance out hypermobile joints by working with strength and stability, but we also don’t want to neglect muscle tightness, and if we’re using a system of objective alignment points, we can effectively stretch our muscles without stretching our ligaments at all. The best of both worlds!

Your reply is self-contradictory. On the one hand you say that the muscles act as brakes against a joint going beyond a certain range (which is true, BTW). You then say that you “work with many yoga students with joint hypermobility and every one of them demonstrates significant corresponding muscle tightness.” If their muscles are tight, then I would expect that they would not be hypermobile (because the brakes would be on). For example, knee hyperextension is one of the measures used to evaluate joint hypermobility syndrome. If the hamstrings are tight, then the knee generally won’t hyperextend.

Since you are claiming that hypermobile people have tight muscles, what is the objective criterion you use to measure the tight muscles? Is it validated in any manner? And what is the criterion you use to diagnose joint hypermobility?

Your reply is self-contradictory. On the one hand you say that the muscles act as brakes against a joint going beyond a certain range (which is true, BTW). You then say that you “work with many yoga students with joint hypermobility and every one of them demonstrates significant corresponding muscle tightness.” If their muscles are tight, then I would expect that they would not be hypermobile (because the brakes would be on). For example, knee hyperextension is one of the measures used to evaluate joint hypermobility syndrome. If the hamstrings are tight, then the knee generally won’t hyperextend.

You also say, “And I also wonder what definition you’re working with when you refer to “tight” muscles: short, hypertonic, unyielding, etc.?”

I see this as obfuscation, frankly. I don’t refer to “tight” muscles; you do. Since you are claiming that hypermobile people have tight muscles, what is the objective criterion you use to measure the tight muscles? Is it validated in any manner? And what is the criterion you use to diagnose joint hypermobility?

As a physical therapist and yoga teacher, I love that this article is being read so widely! I’d like to chime in with one point: the standards of “normal range of motion” are largely from small samples of middle aged men in the 70s. A broader view of normal range of motion recognizes huge variety person to person. Therefore technically you can’t say that full eka pada rajakapotasana requires hypermobility. Quite a few children can take this shape very easily, which brings me to my second point: both data and common sense recognize a loss in range of motion and nearly all body parts with aging. If you start with 100% of your range, but only use 60%, your range shrinks over time. Hence, the older we are, the less mobility we have in our joints. The body is efficient, giving up what it doesn’t need. If you keep exploring your full range of motion, as we attempt in asana (yes, hopefully mainly via muscle stretch, though there are exceptions where you do want joints to gain motion) you get to enjoy sustaining this quality of youth, and it can be highly functional in our lives. So keep playing at the edge of your capacity in an honest way (recognizing, for example, when you are avoiding the hip flexor stretch in eka pada..), emphasis on playing not pushing 🙂

I have 4 words for that: “internally rotated hip joints”. I had been born with those, Doc.
I have pictures from when I’d been a kid (I know it had been an eternity ago). No sitting Indian style in any of them with any comfort.

I have very hypermobile elbows. I was born like that. I saw a photo of myself recently where I must have been about 6 years old, and my arm is stretched out to the side, and my elbow is extremely overextended even back then! So, while it may be a thing that happens over time, like the article suggests, it can also just be the way a person is born. Several of my other joints are like that too; always have been.

I don’t claim any special knowledge of anatomy, so I’m interested in the comments of those who do have such knowledge. However, this is what I observe. If you compare the pictures of Mr. Iyengar doing Rajakapotasana I in Light on Yoga with the picture of the yogi that illustrates this article, I think you’ll see that Mr. Iyengar as he bends back appears to be extending up through the lower back with the abdominals fully engaged while the yogi pictured here appears to be relying more on the mobility (or hypermobility) of her lumbar.

Per the statement that hypermobile people have tight muscles, I wonder if this has more to do with those people saying their muscles are tight in comparison to their joints vs the muscles actually being tight. I am very hypermobile myself and my kneecap dislocated about a year ago just by standing up from seated. My physical therapist (an expert on joint hypermobility btw) has told me that I don’t need to stretch my muscles much because they will always feel tight, even though they are in fact not tight, since they will never stretch as far as my [hypermobile] joints. So hypermobile people don’t in fact have tight muscles (who knows, maybe some do, but I would wager most don’t) but because their joints are so loose, the muscles always feel tight in comparison.

Anyway this is a great topic and definitely deserves more discussion. A lot of people don’t recognize how harmful it can be to hyperextend their joints until they encounter a bad injury.

Wow- I came across this article by accident and am sitting here (in pain from aerial yoga yesterday- ironically) going A HA! I am messing up my back so badly- and I am making it worse by insisting that it needs to stretch to extremes like I’ve been doing.

I’m going to send this to my yoga teacher (I’m in the Netherlands, and doubt this is discussed much here) and see what she thinks. I have been seeking help for my back, but I think I push it too far. Thank you!

Great post! My only question is, what is normal range? I am well aware of normative ranges of motion suggested in various books, however, do they really reflect what is ‘normal’ or do they simply reflect the range of motion of the average person who may or may not be working on their flexibility? My field of interest is dance science and I personally find that comparing dancers’ range of motion with normative data is not reflective of their ‘normality’ as such, due to the fact that they have worked on developing their flexibility (and not hypermobility hopefully, when done right), when compared to the average person. While I think you are perfectly right in proposing we reconsider how we teach or practice yoga, my only suggestion would be that we also need to re-consider whether normative rates for range of motion can be applicable to an advanced yogi, dancer, gymnast etc. I would be very interested in other peoples’ thoughts! 🙂

I love this article. I am a yoga teacher and am very flexible. Not hyper-mobile. I understand how to describe the stretch and lengthing for fascia and muscle tissue. However, I have several Hyper-mobile students. I am interested in knowledge that could help me teach safety for these students. Any tips or direction for this information? I always teach “if it hurts don’t do it” and “listen to your body, it knows best”. However, cues for ligament strain are not familiar to me. Thank you!

I keep being told by yoga instructors that I ‘just don’t have the body’ to do some poses. They normally say it with a kind of pity, like oh what a shame, you’ll never be able to do king pigeon. Normally in a room full of pretzels, who, I realize now, absolutely are hypermobile.

After reading this, I’m….kind of glad? Because when I do yoga, oh BOY do I feel a muscular stretch. I’d rather be stable and strong and stretching muscle. This is a MUCH needed reminder for me!

This was really informative – thank you. However I’m a hypermobile dancer and it’s all about aesthetics and competition for us. Do you have any advice for counteracting the negative effects of hyperextension?